This invention relates to a search system and a search method.
Hitherto, there is disclosed a technology for extracting metadata from raw data as an extraction source of the metadata, storing the raw data and the metadata in association with each other, and analyzing data using the metadata (for example, refer to JP 2011-221799 A).
There is also disclosed a technology for processing various types of “big data” (for example, refer to JP 2012-256324 A). In the technology disclosed in JP 2012-256324 A, an integrated data management system is constructed of more than one data management system. External applications or users access the integrated data management system using a unified interface. Raw data corresponding to a foreign data object is transmitted to be stored in any one of storage modules of a plurality of coupled data management systems based on a plurality of predetermined characteristics (for example, including size or data type). On the other hand, metadata corresponding to a foreign data object is stored in a specific data storage module irrespective of where the raw data is stored.
In this way, the above-mentioned related art executes extraction and writing of metadata and writing of raw data in series. In other words, the related art confirms that the raw data is already written and then stores the metadata. Therefore, the above-mentioned related art confirms whether or not the raw data is already written when storing the metadata, and when the raw data is present, the above-mentioned related art stores the metadata. On the other hand, when the raw data is not present, the above-mentioned related art buffers the metadata temporarily, and writes the metadata as well after storing the raw data.
However, in the above-mentioned related art, the metadata is written only after the raw data is written. Accordingly, when the raw data or metadata needs to be searched for in real time, it is necessary to wait until the raw data is written. As a result, the performance of extraction and writing of metadata is affected by the performance of writing of raw data, thereby causing a problem of degrading reed time performance. Further, when the writing of metadata is completed before the writing of its raw data, an error occurs when trying to search with the metadata to refer to its raw data because the writing of the raw data is not yet completed.
Further, there is a problem in that it is difficult to manage a shared memory between the extraction and writing of metadata and the writing of raw data. In other words, the extraction and writing of metadata and the writing of raw data compete for a lock and hence the performances of the extraction and writing of metadata and the writing of raw data deteriorate. For example, when the performance of the extraction and writing of metadata deteriorates, counting of metadata is delayed, thus leading to a difficulty in ensuring the real time performance.